This invention is directed to a method of producing fully encircling, curved leg elastics. The method involves placing a pair of elastic ribbons on a pair of semi-curved pucks, each puck having a curved surface adjacent a preferably curved top surface, and subsequently applying the elastic ribbons to a substrate.
Pant-like absorbent garments, such as adult incontinence wear, as well as infant and children""s diapers, swim wear and training pants, typically include a pair of leg openings having an elastic portion around each leg opening. The elastic portions are intended to fit snugly around a wearer""s legs to prevent leakage from the garment.
Various technologies are known for applying leg elastics to such articles. For example, one technology involves bonding a continuous loop to a substrate. However, producing a supply of continuous loops of elastic strands is more costly and cumbersome than providing a supply of a continuous length of elastic ribbons.
Articles which incorporate conventional elasticized margins and conventional barrier flap configurations at their leg openings have, however, exhibited various shortcomings. For example, it has been difficult to avoid pressure-induced marking of the wearer""s skin and difficult to maintain the desired gasketing of the leg openings when the articles are being worn. Even when the leg openings are fitted with an elastomeric material or otherwise elasticized, it has been difficult to maintain contact between the leg opening and the wearer""s body for an effective containment of urine and feces. As a result, there has been a continued need for improved containment structures at the leg regions of the absorbent articles.
There is a need or desire for a process for making comfortable, gasket-like leg elastics that are aesthetically pleasing and can be applied in a high-speed application.
The present invention is directed to a method of applying curved leg elastics to pant-like absorbent garments using semi-curved pucks. The result is a comfortable, flexible, aesthetically pleasing leg opening. Furthermore, the resulting leg opening is form-fitting and acts like a gasket.
Apparatus that can be used for carrying out the invention includes a pair of rotating devices, with at least one corresponding semi-curved puck attached to a periphery of each of the rotating devices. Each puck has a first curved surface adjacent a preferably curved second surface. The apparatus also includes a pair of cutting devices and a pair of bonding devices.
In carrying out the invention, each elastic ribbon of a pair of elastic ribbons is guided onto one of the pucks on one of the rotating devices, deflected to conform to the first curved surface of the puck, and cut off with a cutting device after conforming to a length of the first curved surface of the puck. The elastic ribbons are guided onto the pucks such that a portion of each of the elastic ribbons overhangs the edge of the first curved surface of the corresponding puck. Tension in the elastic ribbon causes the overhanging portion to fold over onto the adjacent second surface of the puck around which the elastic ribbon is stretched. Alternatively, the elastic ribbons may already be in discrete lengths prior to carrying out the method of the invention. A vacuum and/or friction surface is used to hold the elastic ribbons in place on the pucks. The rotating devices continue to advance the pucks toward the bonding devices. While the rotating devices rotate, the pucks are radially displaced from a position at which the elastic ribbons are guided onto the pucks to a position wherein the second surfaces of the pucks are substantially parallel to a substrate. Once the pucks are substantially parallel to and in contact with the substrate, the portions of the elastic ribbons folded onto the second surfaces of the pucks are bonded to the substrate. The substrate is typically a liner or an outer cover of the absorbent garment.
The method of the invention can be used in high-speed applications, namely applications running at linear speeds of 600 feet per minute or greater. More than one corresponding pair of semi-curved pucks can be located on the peripheries of the rotating devices to enable a more expedient process. The rotating devices can be adjusted to change pitch or machine direction spacing between adjacent pucks from the point of application of the elastic ribbons to the pucks to the point where the elastic ribbons are transferred and bonded to the substrate.
The substrate may be stretchable or extensible, thereby providing great flexibility and enabling the elastic ribbons to be applied at low tension. Furthermore, stretchability and/or extensibility of the substrate provide for a larger leg fit range.
The resulting product is an absorbent garment having a comfortable, aesthetically pleasing, finished look about the leg openings. This method can also be used to apply curved standing leg cuffs and/or curved leak guard flaps.
With the foregoing in mind, it is a feature and advantage of the invention to provide a method of applying curved leg elastics to an absorbent garment.
It is another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in gasket-like leg openings.
It is yet another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in form-fitting leg openings.
It is a further feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in comfortable and aesthetically pleasing leg openings.